If I find a different instance and I want to follow that instance or become a part of that community, I have to sign up on it.. I don't see a way to follow a si

If I find a different instance and I want to follow that instance or become a part of that community, I have to sign up on it.. I don't see a way to follow a single instance and filter it out of the federated timeline. Perhaps I just don't see that option?